Again, skills are different, not greater or lesser.
That's what's called an axiom, because it's a statement that can't really be argued. To disprove it, a valuation of skills would need to be imposed, and any valuation could just as easily be rejected, or turn out to be useless. And I do agree with your axiom.
So, my question is, what conclusions do you derive from the axiom?
Any valuation that is imposed is simply one imposed, not natural, and neither is any value derived from it essential as an attribute of that which is being appraised.